/**
 * 该文件是用于创建一个为count组件服务的reducer，reducer本身就是一个函数
 * reducer函数会接到两个参数，分别为之前的状态preState和动作对象action
 */

 import {Increment,Decrement} from "../constant.js";

 const initState=0;
 export default function countReducer(preState=initState,action){
     // console.log(preState);
     const {type,data}=action;
     switch (type) {
         case Increment:
             return preState+data;
         case Decrement:
             return preState-data;
         default:
             return preState;
     };
 };